Elbow braces are worn to immobilize, rest and protect the elbow joint itself as well as to rest and protect the ulnar nerve, colloquially known as the “funny bone,” that passes from the upper arm to the forearm behind the elbow joint. The ulnar nerve supplies sensation to the small finger and half of the ring finger and supplies motor control to two muscles in the forearm and fifteen muscles in the hand. When the ulnar nerve becomes compressed at or near the elbow, numbness in the ring and small finger ensues along with weakness or paralysis of many of the muscles that control wrist and finger movements. Among other disabilities, the numbness precludes effective use of keyboards, because of inability to feel the keys with the small finger. Without the person having any tactile appreciation of an injury, burns and cuts can occur when the numbness is profound. Moreover, weakness of the muscles controlled by the ulnar nerve causes diminished grip and pinch strengths.
People with ulnar nerve compression thereby have difficulty with such tasks as opening jars and turning keys. Weakness in muscles controlled by the ulnar nerve also leads to loss of dexterity and coordination for small object manipulation, such as fastening buttons or manipulating paperclips.
The ulnar nerve passes behind the elbow in a bony groove which is covered by a fibrous sheet. The ulnar nerve in this area can become compressed by one or both of the following mechanisms: (1) Prolonged direct pressure on the nerve in or near the groove can squeeze away the nerve's blood supply, causing the nerve to stop functioning, at first temporarily, and over time, permanently. Pressure can come from resting the closed (flexed) or semi-closed elbow on hard surfaces such as armrests on chairs or in cars or on table or desk surfaces. (2) The other mechanism by which the ulnar nerve can become compressed is holding the elbow in its closed position for prolonged periods, such as when sleeping curled up or when holding a phone to one's ear. Either mechanism of compression leads to the condition known as cubital tunnel syndrome. Cubitus is Latin for elbow, and tunnel is the groove through which the ulnar nerve passes. One of the nicknames for cubital tunnel syndrome is “stock broker's elbow,” where the person may be on the phone for prolonged periods and at the same time resting the closed elbow and the ulnar nerve on a hard desk surface.
The first steps of treatment for cubital tunnel syndrome are to diminish the time that the elbow is held in a closed position and to diminish the direct external pressure exerted on the nerve. Patients are advised to use a head set for their phone to preclude the prolonged closed-elbow position and to avoid resting their closed elbow on any hard surface.
Many people tend to curl into a fetal position during sleep and rest their hand(s) under their chin. This posture, of course, is quite natural but it applies undesirable pressure on the ulnar nerve overnight. This sleep posture is ingrained from before birth. It is a hard posture to avoid after falling to sleep even if the person consciously positions the elbow in a straight (extended) or nearly straight position before falling asleep. Various means of elbow immobilization have been devised to prevent the sleeping person from unwittingly assuming and sustaining the injurious closed-elbow position.
Elbow extension braces known in the art are typically cylindrical, perhaps with sections of the cylinder cut away, and cover the upper arm and forearm for variable distances above and below the elbow. A simple, homemade elbow extension brace is a bath towel first folded so that it is approximately as wide as the distance from the user's wrist to armpit, and then rolled around the limb with the ensuing, multi-layered cylinder being secured to itself with safety pins. At bedtime, the user slips this thick sleeve over the elbow. The bulk of the fabric and its proximity to the limb precludes the user from comfortably resting in an elbow-closed position.
Another improvisation uses a basketball knee pad slipped over the elbow with the pad portion on the side of the elbow readily visible when looking at one's own elbow (the front surface, the anterior surface). The bulk of the springy padding discourages prolong posturing in the elbow-closed position. Various commercial braces designed specifically for elbow extension and treatment of cubital tunnel syndrome are also available. These braces typically consist of fabric, which either through its own bulk or through the incorporation of rigid or semi-rigid strut(s), maintains its general cylindrical shape even of the user consciously or unconsciously tries to close the elbow. The brace is typically secured to the limb through portions of the fabric being elastic and thereby snuggly conforming to the enclosed limb or through a means of straps secured by hook and loop fasteners or through both methods. At times, a hand therapist or orthotist custom-molds an elbow extension brace out of rigid or semi-rigid material and secures it to the user's elbow area with straps and fasteners.
The braces of the prior art suffer certain inadequacies. They cover the majority of the limb from armpit to wrist and prevent radiation of heat and evaporation of perspiration, thereby causing the limb to become hot and sweaty. Environmental dirt, perspiration, and body oils permeate and adhere to the brace fabric, raising both sanitation concerns and aesthetic concerns. The fabric portion of the brace is difficult to wash, especially if the rigid or semi-rigid struts are permanently attached or enclosed. The braces of the prior art frequently have elasticized fabric or strapping material pressing directly on the ulnar nerve behind the elbow, thereby contributing to the nerve irritation. The most glaring inadequacy of the braces of the prior art is that they do not allow even momentary closing (flexing) of the elbow should the wearer want to scratch his nose or adjust his pillow.